Folding devices are used in exterior mirrors of motor vehicles, wherein the exterior mirror can be adjusted by way of the folding device, in particular via an electrical drive of the folding device, between a driving position (folded out) and a parked position (folded in).
The drive of such a folding device normally comprises an electric motor with a motor shaft, which, for example, may activate, via a worm gear mechanism, a folding movement between the input drive and an output drive of the worm gear mechanism. A worm gear may be firmly pressed onto the motor shaft (motor worm gear). The axial forces which then act on the motor worm gear are absorbed internally in the motor in one direction, and in the other direction for example a housing element supports the motor shaft end.
The clamping dimension of the motor of such a folding device is subject to relatively large tolerances for production reasons. If the space available between a motor carrier and the housing element is too small, the resulting axial seizing causes an unacceptably high operating current of the motor. If however it is too large, on changes in rotation direction, noises are produced by the change in contact of the motor shaft. Because of the high motor rotation speed and the high mass (motor worm gear, motor shaft and sheet stack with copper windings), the pulse on a change of rotation direction is so great that a clear “click” noise is perceptible, which the driver of the motor vehicle finds disturbing.